Method of reducing plant transpiration



June 18, 1968 WATER LOSS GRAMS E. L. RATLEDGE Filed May 15, 1967 METHODOF REDUCING PLANT TRANSPIRATION TIME IN GROWTH CHAMBER- DAYS UnitedStates Patent 0 3,388,992 METHQD 0F REDUCING PLANT TRANSPIRATION EdwardL. Ratledge, Claymont, DeL, assignor to Sun Oil Company, Philadelphia,Pa, a corporation of New Jersey Continuation-impart of application Ser.No. 469,870, July 6, 1965. This application May 15, 1967, Ser. No.638,288

3 Claims. (Cl. 71127) ABSTRAQT OF THE DISCLOSURE A process for enhancingthe effectiveness of a prepared antitranspirant composition consistingessentially of a wax and oil-in-water emulsion containing 0.25 to 5.0parts wax and oil per 100 parts water, said wax being a petroleum waxhaving a melting point in the range of l22160 F. and said oil being apetroleum hydrocarbon oil having a maximum of 8.0 weight percent gelaromatics and a distillation range at 10 mm. Hg abs. of 300500 F. whichprocess comprises admixing 0.25 to 1.0 part of unemulsified petroleumoil of the same characteristics as that disclosed above to the preformedwax and oil-in-water emulsion immediately before applying the emulsionto growing plants and thereafter applying said preformed emulsion withthe additional oil to the plants.

Cross reference to related applications This application is acontinuation-in-part of my copend ing patent application Serial No.469,870, filed July 6, 1965, and is directed to an improvement in theprocess therein disclosed.

Background 0 the invention This invention relates to an improved methodfor stimulating plant growth. This invention particularly relates to aprocess using compositions of emulsified wax and oil to stimulate plantgrowth by regulation of plant transpiration.

It is generally known that growing plants are continually losing waterby a process known as transpiration. It is not generally realized,however, that the loss of water is very large and often constitutes aserious danger to the well-being of the plant. Most of the water whichis taken in by the roots and carried up the vascular tissues is lostinto the air. Microscopic examination of the structure of a leaf showswhy this occurs. The cells of the mesophyll (the green parenchyrnabetween the epidermal layers of a foliage leaf) are in contact with airover much of their total surface. The cell walls of the mesophyll aremoist, and the water in them evaporates into the air just as water inany sort of sponge or open container evaporates 'if it is in contactwith air. As the walls begin to dry out, more water diffuses into themor is imbibed by them from the water within the plant.

The amount of transpiration under average conditions is surprisinglylarge. A sunflower may transpire 276 grams of water per square meter ofleaf surface per hour. A single corn plant may transpire as much asfifty gallons of water in a growing season and a field of corn cantranspire enough water during a single growing season to cover theground on which it grows with seven inches of water. This water is, ofcourse, absorbed from the soil in which the plant grows.

Water evaporates from a plant for the same reasons and in much the samemanner as it evaporates from an open dish or from a wet cloth. However,the rate of transpiration is not constant. It is most rapidin hightemperature, strong wind, bright light, and low humidity, that com-3,388,992 Patented June 18, 1968 bination of factors which most favorsevaporation. If any one of these factors varies, the rate oftranspiration varies accordingly.

Different plants vary greatly in the rates at which they transpire.Plants with thick, heavily cutinized leaves and relatively few stomataand air spaces (such as pines) transpire less rapidly than those withdelicate leaves well provided with stomata and containing large airspaces. In fact, the ability of certain plants to live in very dryregions is dependent partly on their relatively slow transpiration.

If the leaves transpire more rapidly than the roots absorb water or thestem conducts it, then the water content of the plant decreases. Such adecrease in water content first causes the growth of the plant to stop;and if it is continued, the plant Wilts. Efforts are made, therefore, bygrowers of plants to prevent such results, either by adding water to thesoil or by reducing transpiration. The transpiration from a plant may bereduced by removing some of the leaves; this is frequently done duringtransplanting, when the absorptive system (root system) has been partlydestroyed in handling the plants. The same result is accomplished byplants by the shedding of leaves during a prolonged drought.Transpiration may be reduced also by shading the plant, as isaccomplished by white-washing greenhouses in the summer, by increasingthe humidity of the air surrounding the plant, by lowering thetemperature, or by protecting the plant from the wind (as is done, forexample, in orchards, by wind breaks).

As described above, transpiration takes place from two specific areas offoliar plants; that is, the cuticle and the stomata of the leaves.

Through the layer of cuticle forming the surface of all mature leavessome water escapes into the air. This loss of water through the cuticleis spoken of as cuticular transpiration, to distinguish it from waterloss through the stomata which is called stomata transpiration. Theprincipal means by which plants reduce cuticular transpiration is thethickening of the outer wall of the epidermal cells, the presence oflarge quantities of the wax-like material, cutin, in this wall, and theproduction of the closeset rods of wax (the so-called bloom) whichoccurs on many fruits, leaves, and stems and which has the appearance ofa very fine powder.

Plants which grow in arid or semi-arid regions normally have some degreeof the above-described transpiration control mechanism built into theirfoliage. However, plants such as ornamentals or vegetables whichnormally grow in areas of plentiful rainfall do not normally containthis protective mechanism to any significant degree, Therefore, whenthese plants are subject to unusual or prolonged dry spells, or aretransplanted into a dry area, severe damage with the resulting losses ofthese valuable crops often occurs.

The US. Department of Agriculture recently conducted a study of planttranspiration and published its findings in Production Research ReportNumber 87, entitled Research in Plant Transpiration: 1962. The reportstates on pages 42 and 51:

Several (antitranspirant) compounds are presently marketed by commercialcompanies. These compounds, which are latexes, waxes, and plastics, aregenerally applied in foliar sprays or dips. Some are widely used byhorticulturists for reducing transpiration of transplants, bulbs, andChristmas trees. High costs of these compounds prevent extensive use inthe fields of forestry and agronomy. There is also a paucity ofpublished information on the efficiency of the compounds asantitranspirants. For this reason it was deemed necessary to evaluatethem as potential transpiration suppressants.

Specific information pertinent to each compound tested was supplied bythe manufacturer and is included in the appendix. These materials weretested at the manufacturers recommended rate of dilution on beans,Phaseolus vulgaris L. variety red kidney, and on corn, Zea mays veriethDixie 82. These plants grow and transpire rapidly; therefore, they areexcellent for evaluation studies. Transpiration before and afterspraying was obtained by weight differences. (Page 42.)

Compounds evaluated as transpiration snppressants included several latexand plastic compounds, waxes, mer- Most of them did not reducetranspiration without also depressing plant growth. In some casestemperature of cury and fluoride compounds, and e-hydroxysulfonates.treated leaves was elevated to the kill point when the plants wereplaced under high light. (Page 51.)

All of the above clearly points out the continuing and ever presentproblem of crop damage due to excessive water losses by growing plantsduring droughts or prolonged dry spells. As can be seen in the excerptsfrom the U.S. Department of Agriculture report, the problem ofsustaining plant growth by regulation of transpiration without retardingor damaging the plant treated still exists.

It is recognized that waxes and oils alone or in combination havepreviously been utilized in the treatment of some plants. For example,U.S. Patent 1,875,473 teaches stimulating growth of plants by subjectingthe plants to vapors of shale oil in a controlled environment. Thismethod may be effective in controlled environments such as a greenhouse;however, no large scale application of this process is practicable.

U.S. Patent 2,284,970 relates to a method for regulating the abscissonlayer in growing plants by treatment with an auxin and more especiallyto a carrier for the auxin which upon drying will form a protectivecoating so as to insure that the auxin will be absorbed by the plant.

The carrier disclosed in this patent consists of an emulsion containingfrom 23 to 40 parts wax or wax and oil per 47 to 71 parts of water. Theplant treatment consists of coating said plant with the carriercontaining an auxin, at a time prior to that at which abscisson of plantleaves takes place. The object of using the wax-oil emulsion as acarrier for the auxin is to provide a flexible water soluble coating onthe plant which protects the auxin and enables the plant to absorb theauxin at a constant and continuous rate until the supply of auxin isexhausted. Although apparently effective for its intended purpose, itcan be readily recognized that the carrier compositions disclosed inthis patent do not provide, nor were they intended to provide, a meansof regulating plant transpiration.

U.S. Patent 3,129,429 relates to a method of regulating the time atwhich blossoms form on fruit trees. The process involves coating treeswith low melting point wax to inhibit early blossoming and subsequentlate frost damage to trees. The two critical elements of this inventionare tht the tree must be coated with the protecive coating compositionsprior to budding and the wax used to coat the trees must melt within atemperature range which is normally conducive to plant growth in orderto be effective, i.e., within the range of 70l20 F.

As is disclosed above in the U.S. Department of Agriculture report andthe noted U.S. patents, wax and/r oil coatings have been previously usedto achieve various favorable reactions in plant culturing. However,until now no eiiective method of stimulating plant growth by theregulation of plant transpiration has been discovered. I have nowdiscovered compositions and methods to achieve this goal.

Summary of the invention The present invention comprises a method forregulating moisture transpiration of foliar plants thereby stimulatingthe growth of the plant. The present invention relates to an improvedmethod for the application to growing plants of an antitranspirantcomposition comprised of petroleum wax and hydrocarbon oil-in-wateremulsion. The petroleum wax of the compositions used in the presentinvention is characterized as having a melting point in the range of122-160 F., and the petroleum oil is characterized as having a maximumof 8.0 weight percent gel aromatics and a distillation range at 10 mm.Hg abs. of 300-500 F. The wax and oil concentration in the emulsion isin the range of 0.25 to 5.0 parts by weight per parts of water.Specifically the present invention relates to a process for regulatingtranspiration of foliar plants utilizing the preformed emulsiondescribed above wherein just prior to application of the preformedemulsion to the growing plant an additional 0.25 to 1.0 part ofunemulsified oil of the same type as used in the prcformed wax and oilemulsion is admixed into the emulsion and the whole composition is thenapplied to the plants to be treated.

Description of the invention The drawing is provided to illustrate andcompare the water losses of tomato plants treated in accordance with thepresent invention. Curve A illustrates the water losses viatranspiration of untreated tomato plants and serves as a control. CurveB-D illustrates transpiration water losses for plants treated accordingto the methods disclosed in U.S. patent application 469,870 upon whichthe present invention is an improvement. Curve C illustrates the lowerwater losses resulting from the improved retardance of planttranspiration achieved by the method of the present invention.

I have now discovered a method which most nearly reproduces theantitranspirational mechanisms found in plants adapted to moisture-pooror arid environments. By the method of the present invention, any foliarplant can be protected during its growth periods against damaging waterlosses due to excessive transpiration during prolonged dry spells. Thisprotection is achieved without inhibiting plant growth and in effect themethod of the present invention promotes the growth and the fruit orvegetable production of that plant.

Plant transpiration regulation by the method of the present inventioncan comprise a single application of the preformed emulsion having addedunemulsified oil dispersed therein or a specifically timed series ofapplications. Using either procedure the concentration of wax and oil inthe plant treating composition used is an important part of the presentinvention.

The compositions used in the process of the present invention arecomprised of dilute emulsions of specific concentrations and ratios ofpetroleum wax and specific etroleum hydrocarbon oils in water. Thecompositions used in the process of the present invention morespecifically are comprised of the above-disclosed preformed emulsion towhich. has been added just prior to application of the preformedemulsion to the plants to be treated, 0.25 to 1.0 part of unemulsifiedoil per 100 parts of the preformed emulsion. Petroleum waxes usable inthe compositions used in the method of the present invention have amelting point in the range of l22160 F. These petroleum Waxes areprimarily crystalline and distillate paraifin waxes which are obtainedfrom well known dewaxing procedures from waxy lubricating oils such asby solvent dewaxing with a methyl ethyl ketone-toluene mixtures, methylisobutyl ketones, propane, and the like. The precipitated wax crystalsare removed by centrifuging or filtering to form slack wax. Slack waxusually contains up to 20 weight percent oil and can be further purifiedto form scale wax and refined wax which normally contains less than 0.5weight percent oil. These waxes are well known articles of commerce.

The petroleum hydrocarbon oil component of the compositions used in themethod of the present invention, which can serve as the oil used in thewax and oil emulsion as well as the oil added to the preformed emulsionjust prior to applying the emulsion to the plant foliage, preferably isa solvent refined fraction of petroleum oil composed primarily ofparafiinic and naphthenic hydrocarbons and containing less than 8 weightpercent of aromatics. This petroleum oil fraction is characterized asfollows:

Gravity, API/60 F. 31.0-36.0 Viscosity, SUS/ 100 F. 60-120 Viscosity,SUS/210 F 34-38 Flash point, F 300-400 Fire point, F 375-400 Pourtemperature, F --10-+20 Unsulfonated residue, wt. percent (ASTM)92.0-99.9 Refractive index, 77 F 1.46601.4690 Gel aromatics, Wt. percentmax 8.0 Distillation range at 10 mm. Hg Abs.

(ASTM D1160) F.-- 300-500 Two particularly important elements of thepresent invention are the melting range of the wax used and thecomposition of the petroleum hydrocarbon oil which is used. First it isimportant that the thin film deposited on the surface of the plantstreated according to the method of the present invention maintain itsfilm-like characteristics during the time of transpiration regulation onthe plant. If the melting point of the wax used in the coating is toolow, the wax can become liquid at temperatures favorable to plant growthwhich happening removes the transpiration regulation qualities from thefilm coating which renders the coating ineffective for its intendedpurpose. Also this resulting liquid from the melted Wax under somecircumstances can penetrate the cuticle of the leaf and interrupt thenormal metabollic processes of the plant. Therefore, it is critical thatthe melting point of the wax used in the compositions of the presentinvention be no lower than 122 F.

The compositions used in the method of the present invention are wax andoil-in-water emulsions. Ionic or nonionic surface active compounds canbe employed as emulsifying agents, normally in the concentration rangeof 1 to 10 parts by weight of emulsifying agent for every 100 parts ofwax and oil in the emulsion composition.

Surface active agents are suitable as a class for use according to thepresent invention. The nature of surface active agents is well known,and such agents generally have an oleophilic portion of the molecule,usually of hydrocarbon nature, and another polar portion of themolecule, which may be provided by various functional groups such ashydroxyl, sulfate, carboxyl, carbonyl, amino, nitro, amido, ether,sulfonate, phosphate, phosphite, etc. Examples of suitable classes ofsurface active agents which can be employed are: alkali metal salts offatty acids, alkali metal salts of sulfated fatty acids, fatty acidglycerides, sulfonated or sulfated fatty acid esters or amides, alkalimetal alkyl sulfates, alkali metal alkyl sulfonates, alkali metal arylsulfonates, alkali metal alky1-laury1 sulfonates, quaternary ammoniumhalides, akali metal salts of alkylated naphthalene, sulfonic acid,polyethylene sorbitol esters of fatty acids, fatty acid amides oralkanol amines, condensation products of ethylene oxide and polyalkyleneglycols, sorbitan esters, alkyl substituted phosphoric acids, alkalimetal salts of alkyl phenol sulfonates, etc. Examples of individualsurface active agents, which can be employed are given for example inKirk et al., Encyclopedia of Chemical Technology, vol. 13, pages 515-517 (1954).

Particularly suitable surface active agents for use ac- 'cording to theinvention are the polyalkyl amines and fatty acid amines, sorbitanesters of polyoxyethylene glycol, and others of which numerous examplesare given in the Kirk et al. disclosure referred to in the precedingparagraph.

The compositions of the present invention are normally prepared as anemulsion concentrate which can then be diluted to the preformed emulsioncontaining the desired amount of wax and oil in water. The concentrationof wax and oil in water of the final coating product is an essentialpart of the present invention. If the concentration of wax and oil istoo high in the coating emulsion at the time of application, thedetrimental effects noted in the United States Department of AgricultureReport cited supra can result. Therefore, it is an essential andcritical part of the present invention that the final concentration ofemulsified wax and oil in the preformed emulsion for plant applicationbe no greater than a total of 5.0 parts of wax and oil in parts of waterby weight. Plant growth stimulation can be realized by application of anemulsion coating composition containing as little as 0.25 part of waxand oil in 100 parts of water. However, the preferred concentrationrange of wax and oil in water as a plant treating emulsion is from onepart wax and oil in 100 parts of water to 2.5 parts of Wax in oil in 100parts of Water.

The ratio of emulsified wax to emulsified oil in the preformed emulsioncomposition can vary from 1 part wax to 39 parts oil up to 39 parts waxto 1 part oil by weight according to the desired application. Therefore,the wax and oil emulsion used in the method of the present invention cancontain 0.125 to 4.875 parts of emulsified wax per 100 parts of waterand 0.125 to 4.875 parts of oil per 100 parts of water. Therefore, thesum total of emulsified wax and emulsified oil in the final dilution ofthe emulsion composition for foliar application cannot exceed 5 .0 partsof water for purposes of the present invention.

However, the quantity limitation to the quantity oil in the emulsifiedform in the preformed emulsion does not include unemulsified oil whichcan be admixed into the preformed emulsion just prior to plantapplication. This quantity of 0.25 to 1.0 part unemulsified oil added tothe preformed emulsion is over and above the quantity of emulsified oilin the emulsion.

The unemulsified oil is mixed into the diluted Wax and oil-in-wateremulsion with light agitation just prior to applying the emulsion to thefoliar plants. It is believed that large droplets of the unemulsifiedoil are dispersed uniformly throughout the emulsion.

The mechanism by which the addition of the unemulsified oil to the waxand oil-in-water emulsion just prior to application of the emulsion isnot fully understood. It is believed that the unemulsified oil whenhomogeneously dispersed in the diluted wax and oil emulsion serves tomore effectively wet the foliar surfaces of the plant and therebyprovide more uniform coating by the wax and oil emulsion thus resultingin more efiective regulation of the plants transpiration withoutinhibiting plant growth.

To illustrate the present invention, the following examples are given.

EXAMPLE I At a temperature of F. 30 parts of petroleum parafiin waxhaving a melting point of 126 F. were blended with 30 parts of apetroleum oil fraction of the following characteristics:

Gravity, API/60 F. 34.6 Viscosity, SUS/ 100 F. 70.4 Viscosity, SUS/210F. 36.5 Flash point, F. 355 Fire point, F. 395 Pour temperature, F. 5Unsulfonated residue, wt. percent 95.3 Refractive index, 77 F. 1.4685Gel aromatics, wt. percent 7.7 Distillation range at 10 mm. Hg F 356-475To this blend were added 3.5 parts of polyoxyethylene (20) sorbitanmonooleate which is commercially sold under the trade name Tween 60 byAtlas Powder Company, 3.5 parts of sorbitan monostearate which iscommercially sold under the trade name Span 60 by Atlas Powder Company,and 40 parts of water which had been preheated to the temperature of awax-oil blend. The resulting mixture was then agitated to produce ahomogeneous stable wax and oil emulsion concentrate.

This concentrate was then diluted with water to a final composition of0.5 part wax and oil to 100 parts water. Pepper plants which were beinggrown in sash beds and which had blossomed and started to bear fruitwere transferred from the sash beds in which they were growing to openfields during the month of May, in an area which was experiencing aperiod of below normal rainfall. Approximately one acre of land wasutilized for these pepper transplants which were planted 4 feet apart in50 foot rows. One-half of the plants transplated were sprayed with theabove plant growth stimulating composition in the amount of 100 gallonsper acre.

Standard commercial agricultural spray apparatus was used in the presentapplication and in general is suitable for the purposes of the presentinvention.

The plants of the other half of the acre were left untreated to serve asa control. Sixteen days after treatment all of the plants wereharvested.

The plants of the untreated half of the acre yielded an average of 4full grown peppers per 50-foot row of plants. The average weight ofpeppers harvested per 50- foot row of plants was 1.0 pound. The harvestfrom the plants of the treated half of the acre yielded an average of 18full grown peppers per 50-foot row which peppers average 4.5 pounds per50-foot row of plants harvested. This fourfold increase of fruit yieldin a given amount of time under identical growing conditions clearlydemonstrates the plant growth stimulating effect of the process andcompositions given in this invention. This example sets forth the methodand compositions of Us. patent application Serial No. 469,870 of whichthe present case is a continuation in part. The following exampleillustrates the improvement achieved by the method of the presentinvention over the process disclosed in the above-noted parent patentapplication.

EXAMPLE II A growth chamber provided with facilities to maintain acontrolled environment was set up to provide the following conditions:

Relative humidity, 80%

12 hours of daylight (provided by special electrical lights to simulatesunlight) 12 hours of night (lights off) emperature during daylighthours, 80 F. (lights on) Temperature during night hours, 60 F. (lightsoff) Forty tomato plants averaging approximately 6 to 8 inches inheight, each separately growing in a 250 ml. soil filled flower pot,were transferred from a green house to the test chamber and separatedinto 4 lots of 10 which are designated as lots A, B, C, and D. The lotswere tested in the following manner.

Lot A: these plants were given no treatment and provided a control.

Lot B: these plants were sprayed with the composition dis-closed inExample I in the identical manner as disclosed in Example I.

Lot C: these plants were treated in the identical manner as the plantsof Lot B with the exception that just prior to spraying the plants withthe dilute wax and oilin-water emulsion unemulsified oil of thecharacteristics disclosed in Example I was blended with the emulsion inthe amount of 0.25 part oil per 100 parts of emulsion.

Lot D: a composition identical to that of Example I with the exceptionthat the emulsion concentrate was prepared with 60 parts of oil insteadof as disclosed in Example I. The emulsion concentrate was diluted to aconcentration of 0.75 part emulsified wax and oil in 100 parts of waterand applied to this lot of tomato plants in the identical manner asdisclosed for Lot B.

The moisture of the soil for each potted tomato plant was set at fieldcapacity. Each pot was then individually sealed inside a polyethylenefilm wrapper with the stem and foliar parts of the tomato plant beingoutside of the 8 r film and subject to ambient conditions of the growthchamber.

The potted tomato plants were then subject to growing conditions in thegrowth chamber as described above. Each individual plant was weighed atthe beginning of the period and again at 24-hourintervals thereafter fora period of four days. The measured weight loss after each 24-hour timeinterval was attributed to water losses via transpiration. The resultsof these measurements are illustrated in the drawing.

Now referring to the drawing the curve labelled A represents the averageweight loss for the plants of Lot A. The curve labelled B-D representsthe average water loss for the plants of Lots B and D, each of whichnearly average the same loss rate and can therefore he represented by asingle curve. Curve C represents the average water loss for the plantsof Lot C.

The rate of plant water loss of Lots B, C, and D as represented bycurves B and 0-D when compared with the control as represented by curveA illustrates that the wax and oil emulsion compositions are effectiveantitranspirants. Also a comparison of the curve C-D with curve Bfurther illustrates that the addition of a small quantity ofunemulsified oil to the preformed wax and oil emulsion just prior toapplication of the emulsion of the foliar parts of plants surprisinglyfurther enhances the effect of the antitranspirant. The application ofthe antitranspirant composition by the method of the present inventionresults in effective retardance of the water losses of the plant,thereby stimulating plant growth particularly during periods of droughtor inadequate rainfall.

Each type of plant has individual requirements as to the total wax oilconcentration in the plant foliar treating emulsion as well as the ratioof wax to oil within that emulsion coating composition. For example, theleaf structure of a tomato plant is distinctly different from the leafsturcture of a cucumber plant or a corn plant. As previously noted theleaf structure of the plant is an important factor in regulation oftranspiration of that particular plant, so that the foliar treatingemulsion formulation which most favorably stimulates plant growth foreach type of plant should be selected in accordance with therequirements of that plant.

It has also been discovered that often when the more diluteconcentrations of the emulsions of the present invention are applied toplants at predetermined time intervals during the growing season, plantgrowth is more favorably stimulated than when a single application of anemulsion having higher wax-oil concentrations is made.

The process of the present invention is applicable to all foliar plantsincluding vegetables, trees, ornamentals, and grass.

Vegetable plants such as cucumbers, peppers, tomatoes, green beans,spinach, cabbage and others are included as plants that can be treatedby the method of this invention. In general all decidious and conferoustrees such as oak, elm, maple, spruce,.pine, and others are included asplants which can be treated according to the methods of the presentinvention. All grasses such as fescues, narrow blade and wide bladevarieties as well as ornamentals such as flowers and evergreen bushesare included also as plants which can be treated according to themethods of the present invention.

By topical application is meant the act of coating foliar parts of theplants being treated. Topical application can be in the form of dipping,spraying, or any of the many well known methods of treating growingplants.

The amount of the plant growth composition that is needed to protectgrowing plants is determined by the method of application. When thefoliar surfaces of the plants being treated are sufficiently wetted, theapplication is complete. The amount of treating emulsion necessary tocoat an acre of growing plants is dependent upon the size and number ofplants per acre in the area being treated, as well as the efficiency ofthe method being 9 used. These variables are easily determined withoutexcess experimentation.

Other additives which are known plant adjuvants may be included in thecompositions used in the method of the present invention. Theseadjuvants include fungicides such as metal salts and organic complexesof metals; for example, ferric dimethyldithiocar'bonate, coppercarboate, copper 8-hydroxyquinoleate, copper oleate, copper3-phenylsalicylate, n-dodecylquanidine acetate, and others.

I claim:

1. In a method of reducing plant transpiration which comprises treatingplant foliage with an antitranspirant composition comprising a preformedaqueous emulsion of petroleum wax having a melting point in the range of122-160 F., petroleum hydrocarbon oil characterized as having a maximumof 8.0 weight percent gel aromatics and a distillation range at 10 mm.Hg abs. 300500 F. and an emulsifying agent, the total concentration ofsaid wax and oil being in the range of 0.25 to 5.0 parts per 100 partsof water and comprising 0.125 to 4.875 parts wax and 0.125 to 4.875parts oil, the improvement of enhancing the etfectiveness of theantitranspirant com position Which comprises, just prior to applyingsaid preformed aqueous emulsion to the plant to be treated, mixing intosaid emulsion 0.25 to 1.0 part per 100 parts of the dilute emulsion ofunemulsified hydrocarbon oil of the same characteristics as the oil inthe emulsion and thereafter treating said plants with the resulting admixture.

2. A method according to claim 1 wherein said plant is a tomato plant.

3. A method according to claim 1 wherein said plant is a pepper plant.

References Cited UNITED STATES PATENTS 1,875,473 9/1932 McKee 71--772,248,400 7/1941 Avery 7196 2,284,970 6/1942 Avery 71---96 3,129,5294/1964 Rumsey et al. 71127 JAMES O. THOMAS, JR., Primary Examiner.

